DUNCAN PUBLIC UTILITIES AUTH
NPDES ID: OK0026638
S — SNC: Compliance schedule violation
The facility missed a deadline in its compliance schedule by more than 90 days.
This quarter: 2 reporting violations.
Violations
December 31, 2025
Chromium, sludge, total, dry weight [as Cr]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (SINGSAMP)
DMR, Monitor Only - Overdue
Chromium, sludge, total, dry weight [as Cr]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (ALLWCONC)
DMR, Monitor Only - Overdue
Unit w/liner/leachate collection system
0% over limit
Discharged 0 pass=0;fail=1 against a permitted limit of 0 pass=0;fail=1 (VALUE)
DMR, Monitor Only - Overdue
Copper, dry weight
0% over limit
Discharged 0 mg/L against a permitted limit of 4300 mg/L (MAXIMUM)
DMR, Limited - Overdue
Nickel, sludge, total, dry weight [as Ni]
0% over limit
Discharged 0 mg/L against a permitted limit of 420 mg/L (MAXIMUM)
DMR, Limited - Overdue
Cadmium, dry weight
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (SINGSAMP)
DMR, Monitor Only - Overdue
Lead, sludge, total, dry weight [as Pb]
0% over limit
Discharged 0 kg/ha against a permitted limit of 300 kg/ha (MX VALUE)
DMR, Limited - Overdue
Selenium, dry weight
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (SINGSAMP)
DMR, Monitor Only - Overdue
Pollutant table from 503.13
0% over limit
Discharged 0 table # against a permitted limit of 0 table # (VALUE)
DMR, Monitor Only - Overdue
Molybdenum, sludge, total, dry weight [as Mo]
0% over limit
Discharged 0 kg/ha against a permitted limit of 0 kg/ha (MX VALUE)
DMR, Monitor Only - Overdue
Molybdenum, sludge, total, dry weight [as Mo]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (SINGSAMP)
DMR, Monitor Only - Overdue
Copper, dry weight
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (SINGSAMP)
DMR, Monitor Only - Overdue
Toxicity characteristic leaching procedure
0% over limit
Discharged 0 pass=0;fail=1 against a permitted limit of 0 pass=0;fail=1 (MO AV MN)
DMR, Monitor Only - Overdue
Ann. amt sludge disposed by other method
0% over limit
Discharged 0 kg/d against a permitted limit of 0 kg/d (ANNL TOT)
DMR, Monitor Only - Overdue
Selenium, dry weight
0% over limit
Discharged 0 mg/L against a permitted limit of 100 mg/L (MAXIMUM)
DMR, Limited - Overdue
Molybdenum, sludge, total, dry weight [as Mo]
0% over limit
Discharged 0 mg/L against a permitted limit of 75 mg/L (MAXIMUM)
DMR, Limited - Overdue
Level of pathogen requirements achieved
0% over limit
Discharged 0 state class against a permitted limit of 0 state class (SINGSAMP)
DMR, Monitor Only - Overdue
Arsenic, dry weight
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (SINGSAMP)
DMR, Monitor Only - Overdue
Mercury, sludge, total, dry weight [as Hg]
0% over limit
Discharged 0 kg/ha against a permitted limit of 17 kg/ha (MX VALUE)
DMR, Limited - Overdue
Nickel, sludge, total, dry weight [as Ni]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (ALLWCONC)
DMR, Monitor Only - Overdue
Annual amt. sludge disposed surface unit
0% over limit
Discharged 0 kg/d against a permitted limit of 0 kg/d (ANNL TOT)
DMR, Monitor Only - Overdue
Lead, sludge, total, dry weight [as Pb]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (SINGSAMP)
DMR, Monitor Only - Overdue
Nickel, sludge, total, dry weight [as Ni]
0% over limit
Discharged 0 kg/ha against a permitted limit of 420 kg/ha (MX VALUE)
DMR, Limited - Overdue
Nickel, sludge, total, dry weight [as Ni]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (SINGSAMP)
DMR, Monitor Only - Overdue
Annual amt sludge transported interstate
0% over limit
Discharged 0 kg/d against a permitted limit of 0 kg/d (ANNL TOT)
DMR, Monitor Only - Overdue
Cadmium, dry weight
0% over limit
Discharged 0 kg/ha against a permitted limit of 39 kg/ha (MX VALUE)
DMR, Limited - Overdue
Arsenic, dry weight
0% over limit
Discharged 0 kg/ha against a permitted limit of 41 kg/ha (MX VALUE)
DMR, Limited - Overdue
Lead, sludge, total, dry weight [as Pb]
0% over limit
Discharged 0 mg/L against a permitted limit of 840 mg/L (MAXIMUM)
DMR, Limited - Overdue
Arsenic, dry weight
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (SINGSAMP)
DMR, Monitor Only - Overdue
Mercury, sludge, total, dry weight [as Hg]
0% over limit
Discharged 0 mg/L against a permitted limit of 57 mg/L (MAXIMUM)
DMR, Limited - Overdue
Copper, dry weight
0% over limit
Discharged 0 kg/ha against a permitted limit of 1500 kg/ha (MX VALUE)
DMR, Limited - Overdue
Annual amount of sludge land applied
0% over limit
Discharged 0 kg/d against a permitted limit of 0 kg/d (ANNL TOT)
DMR, Monitor Only - Overdue
Vector attraction reduction alternative used
0% over limit
Discharged 0 alt # against a permitted limit of 0 alt # (VALUE)
DMR, Monitor Only - Overdue
Description of pathogen option used
0% over limit
Discharged 0 alt # against a permitted limit of 0 alt # (VALUE)
DMR, Monitor Only - Overdue
Mercury, sludge, total, dry weight [as Hg]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (SINGSAMP)
DMR, Monitor Only - Overdue
Cadmium, dry weight
0% over limit
Discharged 0 mg/L against a permitted limit of 85 mg/L (MAXIMUM)
DMR, Limited - Overdue
Nickel, sludge, total, dry weight [as Ni]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (SINGSAMP)
DMR, Monitor Only - Overdue
Selenium, dry weight
0% over limit
Discharged 0 kg/ha against a permitted limit of 100 kg/ha (MX VALUE)
DMR, Limited - Overdue
Level of pathogen requirements achieved
0% over limit
Discharged 0 state class against a permitted limit of 0 state class (MX VALUE)
DMR, Monitor Only - Overdue
Description of pathogen option used
0% over limit
Discharged 0 alt # against a permitted limit of 0 alt # (VALUE)
DMR, Monitor Only - Overdue
Annual amt sludge disposed in landfill
0% over limit
Discharged 451.11360157 kg/d against a permitted limit of 0 kg/d (ANNL TOT)
DMR, Monitor Only - Overdue
Compliance w/part 258 sludge requirement
0% over limit
Discharged 1 pass=0;fail=1 against a permitted limit of 0 pass=0;fail=1 (VALUE)
DMR, Monitor Only - Overdue
Zinc, sludge, total, dry weight [as Zn]
0% over limit
Discharged 0 mg/L against a permitted limit of 7500 mg/L (MAXIMUM)
DMR, Limited - Overdue
Arsenic, dry weight
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (ALLWCONC)
DMR, Monitor Only - Overdue
Zinc, sludge, total, dry weight [as Zn]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (SINGSAMP)
DMR, Monitor Only - Overdue
Arsenic, dry weight
0% over limit
Discharged 0 mg/L against a permitted limit of 75 mg/L (MAXIMUM)
DMR, Limited - Overdue
Vector attraction reduction alternative used
0% over limit
Discharged 0 alt # against a permitted limit of 0 alt # (VALUE)
DMR, Monitor Only - Overdue
Polychlorinated biphenyls [PCBs]
0% over limit
Discharged 0 mg/L against a permitted limit of 49.99 mg/L (ANNL MAX)
DMR, Limited - Overdue
Unit boundary to property line distance
0% over limit
Discharged 0 m against a permitted limit of 0 m (VALUE)
DMR, Monitor Only - Overdue
Zinc, sludge, total, dry weight [as Zn]
0% over limit
Discharged 0 kg/ha against a permitted limit of 2800 kg/ha (MX VALUE)
DMR, Limited - Overdue
Annual sludge production, total
0% over limit
Discharged 451.11360157 kg/d against a permitted limit of 0 kg/d (ANNL TOT)
DMR, Monitor Only - Overdue
Annual amt of sludge incinerated
0% over limit
Discharged 0 kg/d against a permitted limit of 0 kg/d (ANNL TOT)
DMR, Monitor Only - Overdue
September 30, 2025
Oxygen, dissolved [DO]
0% over limit
Discharged 0 mg/L against a permitted limit of 6 mg/L (MINIMUM)
DMR, Limited - Overdue
E. coli
35% over limit
Discharged 548 MPN/100mL against a permitted limit of 406 MPN/100mL (DAILY MX)
DMR, Limited - Numeric Violation
May 31, 2025
Flow, in conduit or thru treatment plant
Limit violation
Discharged 5.08 MGD against a permitted limit of 0 MGD (DAILY MX)
DMR, Limited - Numeric Violation
Flow, in conduit or thru treatment plant
Limit violation
Discharged 6.92 MGD against a permitted limit of 0 MGD (DAILY MX)
DMR, Limited - Numeric Violation
Flow, in conduit or thru treatment plant
Limit violation
Discharged 5.54 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Limited - Numeric Violation
Flow, in conduit or thru treatment plant
Limit violation
Discharged 4.23 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Limited - Numeric Violation
April 30, 2025
BOD, carbonaceous [5 day, 20 C]
28% over limit
Discharged 11.5 mg/L against a permitted limit of 9 mg/L (WKLY AVG)
DMR, Limited - Numeric Violation
Selenium, total [as Se]
318% over limit
Discharged 0.26786 kg/d against a permitted limit of 0.064014 kg/d (MO AVG)
DMR, Limited - Numeric Violation
September 30, 2024
Flow, in conduit or thru treatment plant
Limit violation
Discharged 0.02 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Limited - Numeric Violation
Flow, in conduit or thru treatment plant
Limit violation
Discharged 0.18 MGD against a permitted limit of 0 MGD (DAILY MX)
DMR, Limited - Numeric Violation
Flow, in conduit or thru treatment plant
Limit violation
Discharged 1.34 MGD against a permitted limit of 0 MGD (DAILY MX)
DMR, Limited - Numeric Violation
Flow, in conduit or thru treatment plant
Limit violation
Discharged 0.93 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Limited - Numeric Violation
August 31, 2024
Flow, in conduit or thru treatment plant
Limit violation
Discharged 0.29 MGD against a permitted limit of 0 MGD (DAILY MX)
DMR, Limited - Numeric Violation
Flow, in conduit or thru treatment plant
Limit violation
Discharged 1.6 MGD against a permitted limit of 0 MGD (DAILY MX)
DMR, Limited - Numeric Violation
Flow, in conduit or thru treatment plant
Limit violation
Discharged 1.19 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Limited - Numeric Violation
Flow, in conduit or thru treatment plant
Limit violation
Discharged 0.22 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Limited - Numeric Violation
July 31, 2024
Flow, in conduit or thru treatment plant
Limit violation
Discharged 1.45 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Limited - Numeric Violation
Flow, in conduit or thru treatment plant
Limit violation
Discharged 2.18 MGD against a permitted limit of 0 MGD (DAILY MX)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
111% over limit
Discharged 15.8 mg/L against a permitted limit of 7.5 mg/L (WKLY AVG)
DMR, Limited - Numeric Violation
Flow, in conduit or thru treatment plant
Limit violation
Discharged 0.25 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Limited - Numeric Violation
Flow, in conduit or thru treatment plant
Limit violation
Discharged 0.31 MGD against a permitted limit of 0 MGD (DAILY MX)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
4% over limit
Discharged 5.2 mg/L against a permitted limit of 5 mg/L (MO AVG)
DMR, Limited - Numeric Violation
First flagged
April 14, 2026 (3 months ago)
Last confirmed
July 13, 2026 (23 days ago)